Some medical devices may monitor one or more physiological parameters of a patient on a temporary basis or on a chronic basis. Example sensors include pressure sensors that sense blood pressure or other pressure within the patient, accelerometers that sense muscle movement or patient posture, pulse oximeters or other reflectometers that sense a blood oxygen saturation level of the patient, acoustic sensors that sense cardiac activity, and the like. Some implantable sensors may be optical sensors that include a light source that emits light and a detector that senses the light. The intensity, velocity, phase or wavelength of the emitted light may be modulated in response to changes in a physiological parameter of the patient. The medical device may receive the modulated optical signal and determine a physiological parameter value of the patient based on one or more characteristics of the received optical signal.
For example, a pressure sensor may include a deflectable member that deflects in response to changes in pressure. As the deflectable member deflects in response to changes in pressure, the position or optical properties of the deflectable member may change, which may modulate light that is emitted by a light source of a medical system and traverses through the deflectable member or reflects off of the deflectable member. In this way, one or more characteristics of an optical signal that is generated when the emitted light traverses through the deflectable member may indicate a pressure characteristic of the patient.